Chitin is one of the most abundant polymers on the planet, yet it is highly insoluble and only a few organisms can degrade it down to simple monomers. It is a long chain polymer of N-acetylglucosamine that is produced by crustaceans (crabs, lobster, shrimp), mollusks, cephalopods (squid, octopus), insects, fungi, and yeasts. At present most known chitin degraders are microorganisms that are aerobic heterotrophs. In other words, they require oxygen to metabolize chitin as a source of energy, carbon, and nitrogen. Other chitin degraders require that an independent source of organic compounds be added to the culture medium as an energy source. Thus current schemes to use the microbial degradation of chitin as a source for biomass or biofuel production, large scale culture conditions require abundant aeration and for the oxygen tensions to be carefully monitored and controlled. For some species of microorganism, an external source of carbon and energy must be provided (in the form, for example, of yeast extract). Both of these requirements add significantly to the cost and energy required to carry out large-scale degradation of chitin for the purposes of biomass production.
A need remains for an efficient method that uses the abundant polymer chitin as a nitrogen source to produce biomass, particularly cyanobacterial or algal biomass, on a commercial scale. In order to make the subject process as carbon neutral as possible, the method should replace the use of carbon-intensive materials, such as conventional nitrogen-based fertilizers, with carbon neutral alternatives.